Conventionally, techniques for providing an image of another product related to a product selected by a user to the user in order to encourage the user to purchase the product have been known. For example, Patent Literature 1 discloses a technique for an online shopping mall in which when a user has purchased a product, other products such as shoes, a hat, and a bag that are registered in advance and match the product are introduced, whereby the purchase of the other products is promoted.